When harvesting agricultural crops using a combined harvester-thresher by-products are produced. The by-products are typically straw and chaff however other by-products can also be produced when harvesting various crop types. Unless these by-products are collected and bailed it is important to good farming practice to spread the by-products back over the area they originally occupied before harvesting.
This is particularly the case when employing zero-tillage farming techniques. Furthermore, when employing zero-tillage it is important that the straw component of the by-products be chopped as finely as possible, and for all the by-product to be distributed as evenly as possible.
A number of spreaders for use with harvester-threshers are known. One such is the Kirby spreader as taught in Canadian Patent 2,066,860, issued Nov. 23, 1993, which comprises a plurality of rotating flails arranged above a plurality of spreader fins rotating in an enclosure having an open top to receive straw and chaff therethrough and having an outlet arranged on each side of the enclosure.
The Kirby spreader is designed to be used with harvester-threshers that do not employ a straw choppers. The spreader is operated by placing the spreader directly beneath the straw and chaff outlets of a harvester-thresher. The straw and chaff and other by-products exit the outlets and pass through the rotating flails of the spreader. Large pieces of unchopped straw and some of the other by-products are spread by the flails while the remaining smaller material falls to the spreader fins and are spread thereby. The material spread by the spreader fins exits through the outlets in the enclosure distributing the material a distance laterally outwards from the harvester-thresher forming two spaced apart rows with the large straw pieces spread by the flails lying therebetween.
This process does not work well with a harvester-thresher employing a straw chopper for chopping the straw into the small pieces required for zero-tillage farming. Current choppers chop the straw into small pieces and then deliver all the straw to the ground or to a spreader lying below the chopper. When used with a Kirby or like spreader most of the straw will fall though the flails to the rotating spreader fins. This leads to uneven distribution of the by-products since most of the material ends up in the two spaced apart rows with very little material lying therebetween.
An improved chopper is needed for use with a harvester-thresher and a Kirby type or similar straw and chaff spreader which delivers a portion of the chopped straw rearwards to the ground behind the harvester-thresher and a portion of the chopped straw to the straw and chaff spreader thereby permitting even distribution of the straw and other harvest by-products.